Recovery of wool grease



Patented Feb. 3, 1942 RECOVERY or WOOL GREASE Charles R. Brown, Upper Darby, Pa., asslgnor to The Sharples Corporation, Philadelphia, Pa., a

corporation of Delaware No Drawing. Application December Serial No. 372,011

18 Claims.

The present invention relates to animp'rovement in the processing of wool scouring liquor in order to secure an improved quality of wool grease.

While variations of the invention may be applied to all of the various scouring processes in use, I will particularly describe its application to the crude grease-containing mixture obtained by the process of scouring the wool with a solvent insoluble in water, such as the commonly used organic solvents; e. g., the petroleum solvents. It is well known in the art that the steps of cleaning wool by extraction with a petroleum solvent and subsequently washing it with warm water for the purpose of removing water-soluble impurities result in producing an improved quality of scoured wool, in which the wool fibers retain 'their original strength and elasticity to a remarkable degree.

Wool which has been scoured with soap and alkalies in accordance with the procedure commonly practiced in the United States loses a part of the original strength and elasticity of the fibers, the extent of this disadvantage depending, of course, on the exact nature of use of the detergents in the scouring operation.

The process of scouring the wool by extraction with solvents, followed by washing with warm water, also has an advantage in that the solvent extract contains all of the original grease of the wool except that which is purposely left in the wool. On the other hand, when the wool is scoured with soap and alkalies, the ordinary yield of salable grease is not in excess of 20 or 25% of the grease content of the wool.

From the above discussion, it will be evident that the scouring of wool by the use of organic solvents presents certain very definite theoretical advantages over the more common practice of scouring with soap and alkali. The advantage of improved yield of grease is diflicult to accomplish in practice, however, due to the nature ofthe solvent extract which is obtained when organic solvents are used. Grease which is removed from the wool in the commonly practiced detergent and alkali scouring process can be subjected to refining steps by which it is converted into high grade grease or lanolin. The grease contained in the extract obtained by organic solvent treatment of the wool, on the other hand,

.cannot be economically refined into a high grade product suitable for medicinal or other applications requiring a relatively pure product. As a consequence of this fact. grease obtained from the organic solvent extraction process is ordinarily sold as a crude product for such uses as leather dressing, or .as a component of lubricating greases.

In order that this invention may be more readily understood, I will first describe the method of obtaining wool grease by the solvent extraction of wool. .The wool is leached in closed tanks called fkiers with a solvent in which the wool grease is soluble, preferably a petroleum product such as extraction naphtha. By the performance of this leaching operation, a solvent extract is recovered which may contain approximately 10% wool grease, and which also contains a considerable quantity of other impurities. While the wool suint is insoluble in either naphtha or wool grease alone, the solution of wool grease in naphthe. obtained by the extraction process is a solvent for the suint, and the product obtained by the extraction operation therefore contains a considerable quantity of suint. The naphtha extract is also contaminated by considerable quantities of solid impurities, including fine clay and protein matter in colloidal suspension. In order to recover the valuable wool grease and at the same time recover the naphtha for re-use, the extract is first subjected to a" gravity settling operation to effect removal of a part of the heavy suspended impurities. The liquor from which a part of the impurities have been separated by this settling operation is still in an impure state, however, and this liquor is next bubbled through a weak sulfuric acid solution in order to remove some of the suint and suspended solid from the naphtha extract. The naphtha is next removed from the acid treated product by distillation.

The still bottoms containing the impure wool grease freed of naphtha are 'next mixed with water and centrifugedto recover dry grease. As pointed out above, however, the recovered grease is of poor quality, being dark in color, having a disagreeable burnt odor, and containing between 10 and 15% of free fatty acids. Although the reasons for these objectionable characteristics have no bearing on the present invention, it may be pointed out that they are, to a large extent at least, due to imperfect clarification of the naphtha extract. The sulfuric acid treatment and the heating of the acid treated product in the presence of small quantities of sulfuric acid and substantial quantities of suspended and soluble impurities result in a splitting of the neutral grease to a substantial extent, and in other reactions within the material treated, which result in the production of a low grade wool grease which cannot be refined to produce a substantially higher grade 01' wool grease at any expense the alkali-treated extract.

commensurate with the value of the productwhich mightbe obtained.

The objectof my invention has been to provide a process by which the crude solvent extracts which have been heretofore treated as described above may be economically treated to produce a highly refined wool grease or lanolin.

My invention rests upon the discovery that, when a solution of sodium abietate is agitated with the naphtha extract contaminated as described above, the suspended solids may be removed rapidly and relatively completely from the resulting mixture by a simple separation process, such as ordinary gravity subsidence. At the same time, the suint from the naphtha solution is transferred to the aqueous sodium abietate solution. The aqueous sodium abietate solution, containing the suint, separates as the heavier layer, from the purified wool grease when the mixture is allowed to settle. As a result, there is obtained a mixture consisting of a supernatant clear yellow solution of wool grease in naphtha and an underlying layer consisting of a settled slurry containing a solution of sodium abietate and suint, along with precipitated solid impurities.

The supernatant layer is separated from the impuritiesmhich have been stratified from it as discussed above, and the naphtha is then distilled overhead to leave, as a distillation residue, a relatively pure, light colored, practically odorless wool grease.

In order to secure a wool grease of the highest quality while using the smallest possible amount of reagents, I prefer to perform the clarification as follows. The impure naphtha extract is first subjected to a gravity settling or centrifugal separating operation to remove such heavy dirt as may be separated therefrom without more elaborate treatment. A very small amount of a fairly concentrated alkali solution (e. g., 50% caustic soda solution) is then added to and mixed with the wool grease extract. to be added will depend on the grade of wool from The amount of alkali' which the extract has been made, but in any I event, the amount required will not ordinarily exceed the equivalent of .05% NaOH.

After the addition of the alkaline solution, sufiicient abietic acid is added to exactly neutralize This abietic acid is preferably added slowly, while agitating the mixture. The mixture is preferably warmed to a temperature of between 100 and 110 F. during the addition of the acid. As the abietic acid is added, it reacts with the alkali to form a soluble abietic acid soap, and the resulting soap is in solution in the impure naphtha extract, since only a very small amount of water is present. After completion of the addition of the abietic acid, and neutralization of the free alkali by the abietic acid, water (e. g., 5 to 10%, based on the amount of extract under treatment) is added until the sodium abietate isprecipitated from the extract. Upon precipitation, the sodium abietate carries with it the undesired solid impurities present in the extract. At the same time, any fatty acids which may have been present in the extract are neutralized and removed with the sodium abietate solution formed upon addition of the water, and the insoluble impurities are also precipitated in a form which permits them to be separated rapidly from the wool grease extract by a suitable separating operation, such as gravity settling or centrifugation. After separation of the soluble and insoluble impurities as described above, the resulting wool grease extract is a neusolution in tral product which is free from all of the objectionable impurities which are normally present in cruder grades of wool grease, such as those obtained by the steps of'treating with sulfuric acid and other steps described above in connection with the prior art. The wool grease obtained by the process of the present invention meets all of the specifications of refined wool grease or lanolin, as it is commonly called.

" Example I A-sample of wool was extracted with Stoddard Solvent until the solvent had dissolved an amount of grease which was 10% of its own volume. The resulting solution, which contained suint and insoluble impurities was allowed to settle, and the more easily removable soluble impurities were thus separated from the solution. The partially purified liquor was still very dirty, and contained suint in solution and fine clay and protein matter in suspension.

' 20 cc. of a 35% solution of sodium abietate was layer, was a clear yellow product.

The solvent was next removed from the clarifled extract by distillation with live steam. The residual wool grease was light yellow in color and neutral, and had no disagreeable odor.

Example 11 A second sample of cc. of dirty liquor resultingfrom a'preliminary settling operation, .as

in Example I, was mixed with 0.5 grams of abietic acid. The liquor was warmed to F. to dissolve the aibetic acid. 0.0! cc. of 50% caustic soda solution was then added to the resulting mixture to neutralize this mixture exactly. No separation of impurities from the resulting mixture occurred at the conclusion 'of these operations.

10 cc. of water was then added to the mixture and thoroughly mixed therewith. A break occurred promptly, the solids and soap solution separating rapidly as the heavier layer. The upper layer was a clear yellow neutral product. After separation from the lower layer, this product was distilled with live steam to remove the naphtha.

The residual grease, obtained in this manner, was a light yellow product, and had a. pleasant odor.

While the invention has been described with some particularity above, I wish it to be understood that a number of modifications are possible within the broad spirit of the invention. For example, the invention is of sodium abietate in pure condition, as ordinary commercial rosin may be substituted for abietic acid in the practice of the invention, although the results obtained when rosin is substituted for the pure material are not so good, due to the fact that the finished wool grease will contain the oilsoluble constituents of the rosin. I

While the invention has been described specifically with reference to the treatment of wool grease extracted by hydrocarbons from the wool, it is by no means restricted to this single application. The wool grease may, for example, be extracted by other oil-soluble solvents and the extract then treated as described above. Furthermore, impure wool grease obtained from not restricted to the use wool scouring liquors bycentrifugation or gravity settling may also be treated with sodium abietate or equivalent reagent in order to purify this wool grease, just a the extract is purified in accordance with the process discussed above.

soluble abietic acid salts and closely related salts of other acids may be employed. It is not absolutely necessary that they abietic acid radical be the only acid radical in the purifying agent used in the practice of the invention, since other related naphthenic acid soaps have a similar effect. A mixture of abietic and oleic acids obtained from tall oil may, for example, be employed in the practice of the invention, although it is best that, in the use of any such mixture, the abietic acid be the predominant constituent.

Still further modifications will be obvious to those skilled in the art, and I do not therefore wish to be limited except by the scope of the subjoined claims.

I claim:

1. In the manufacture of a purified wool grease from a crude wool grease contaminated with insoluble impurities and suint, the process comprising mixing with said crude .wool grease an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease.

2. In the manufacture of a purified wool grease from a crude wool grease .contaminated with insoluble impurities and suint, th process comprising mixing with said crude wool grease an aqueous solution of sodium abietate, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease.

3. In the manufacture of a purified wool grease from a crude wool grease contaminated V phase and associated insoluble impurities from the wool grease.

7. In the manufacture of a purified wool grease from a crude wool grease, the process comprising separating suint from the crude wool grease by mixing with said crude wool grease an aqueous solution of an abietic acid salt, and. separating the resulting aqueous phase, containing dissolved suint, from the wool grease.

8. In the manufacture of a purified. wool grease from a solution of crude wool grease in an organic solvent, the process comprising separating from said solution of crude wool grease suint and insoluble impurities by mixing with said cr-ude wool grease an aqueous solution of sodium abietate, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease solution.

9. In the manufacture of a purified wool grease from a solution of crude wool grease in a hydrocarbon solvent, the process comprising separat-,

ing from said solution of crude wool grease suint and insoluble impurities by mixing with said crude: wool grease an aqueous solution of sodium abietate, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease solution.

10. In the separation of a purified wool grease from a solvent extract obtained by leaching of wool with an-organic solvent, the process comprising mixing the crude wool grease extract with an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease.

11. In the separation of a purified wool grease from a solvent extract obtained by leaching of wool with a hydrocarbon solvent, the process comprising mixing the crude wool grease extract with an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease.

with insoluble impurities and suint, the process comprising mixing with said crude wool grease an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease by a gravity settling operation.

4. In the manufacture of a purified wool grease from a solution of crude wool grease in an organic solvent, the process comprising separating from said solution of crude wool grease suint and insoluble impurities by mixing with said crude wool grease an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease solution.

5. In the manufacture of a purified wool grease from a solution of crude wool grease in a hydrocarbon solvent, the process comprising separating from said solution of crude wool grease suint and insoluble impurities by mixing with said crude wool grease an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease solution.

6. In the manufacture of a purified wool grease from a crude wool grease, the process comprising separating insoluble impurities from the crude wool grease by mixing with said crude wool grease an aqueous solution of an abietic 12. In the separation of a purified wool grease from a solvent extract obtained by leaching of wool with a hydrocarbon solvent, the process comprising mixing the crude wool grease extract with an aqueous solution of sodium abietate, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease.

13. In the manufacture of a purified wool grease from a crude wool grease contaminated with insoluble impurities and suint, the process comprising mixing with said crude wool grease an aqueous solution of an abietic acid salt, and

' separating the resulting aqueous phase and associated insoluble impurities from'the wool grease, the mixing of abietic acid salt solution with the crude wool grease being accomplished by mixing said wool grease with a small amount of abietic acid, neutralizing said abietic acid with a base forming a water-soluble salt therewith, and

' thereafter adding sufficient water to the resulting acid salt, and separating the resulting aqueous solution of abietic acid salt in the crude wool grease to effect precipitation of said abietic acid salt from said wool grease and solution of said abietic acid salt in the resulting aqueous phase.

14. In the manufacture of a purified wool grease from a'crude'wool grease contaminated with insoluble impurities and suint, the process comprising adding to said crude wool grease an aqueous solution of an abietic acid salt, mixing said aqueous solution with said crude wool grease, and separating the resulting aqueous phase and associated insoluble impurities from the wool grease.

grease r with abietic acid in rosin.

15. A process as defined in claim 1, in which the abietic acid salt mixed with the crude wool contains salts of other acids associated 18; A process as deiined in clairn l, in which the abietic acid salt mixed with the crude wool grease contains salts 0! other acids associated with abietic acid in tall oil.

[ 17. In the manufacture oi a purified wool grease from a source of crude wool grease, the process comprising mixing the'crude wool grease product with an organic solvent to eitect solution oi wool'greasc and soluble impurities in said solvent and suspension of insoluble impurities in the resulting solution, mixing the resulting crude'wooi grease-containing product with an aqueous, solution of an .abietic acid salt, and separating the resulting aqueous phase and associatedinsoluble impurities from the wool grease.

18. In the manufacture of' a purified wool grease from a source of crude wool mm, the process comprising mixing the crude wool grease product with al drocarbon solvent to eiiect solution of wool grease and soluble impurities in said solvent and suspension of insoluble impurities in the resulting solution, mixing the resulting crude wool grease-containing product with an aqueous solution of an abietic acid salt, and separating the resulting aqueous phase and associated insoluble impurities irom the W001 grease.

CHARLES R. BROWN. 

